With development of the communication industry, especially of the optical communication having broad bandwidth, security of information is of increasing concern. Safety and security have become a chief issue in the communication industry. Common encryption approaches for the optical communication include information encoding encryption, algorithm encryption, frequency hopping encryption as well as quantum encryption which is recently developed. However, the quantum encryption is, so far, just in the experimental phase and is quite far from commercial applications.
The concept of frequency hopping encryption originates from the wireless frequency hopping communication in which a transmitter continuously switches its carrier wavelength according to a frequency hopping pattern and a receiver has to switch its wavelength in the same manner so as to receive complete information. Also, the interference immunity can be improved due to continuous switching of the carrier. As the frequency hopping sequence is randomly generated and thus is irregular, it is difficult to be cracked.
Currently, the algorithm encryption is commonly employed as one applicable to the communication encryption. However, no matter how complicated an encryption algorithm is, there is a certain degree of regularity. Thus, it can be cracked by analyzing the regularity of data variation.
According to the present invention, the algorithm encryption and the frequency hopping encryption are combined to provide a novel data encryption method by which it is possible to encrypt transmission data without losing the advantage of broad bandwidth of the optical communication.